Tubular woven fabrics have been used for soft-tissue implantable prostheses to replace or repair damaged or diseased lumens in the body. In particular, endoprostheses are used in the vascular system to prevent the blood from rupturing a weakened section of the vessel. Such endoluminal conduits are generally affixed in a specified location in the vessel by means of stents, hooks or other mechanisms which serve to secure the device in place. Endoluminal tubular devices or conduits can also be used in other lumens in the body, such as in the esophagus and colon areas.
Weaving is commonly employed to fabricate various tubular shaped products. For example, implantable tubular prostheses which serve as conduits, such as vascular grafts, esophageal grafts and the like, are commonly manufactured using tubular weaving techniques, wherein the tubular product is woven as a flat tube. In such weaving processes, a variety of yarns are interwoven to create the tubular fabric. For example, a set of warp yarns is used which represents the width of the product being woven, and a fill yarn is woven between the warp yarns. The fill yarn is woven along the length of the warp yarns, with each successive pass of the fill yarn across the warp yarns for each side of the tube representing one machine pick. Thus, two machine picks represent one filling pick in a tubular woven structure, since weaving one fill yarn along the entire circumference of the tube, i.e., one filling pick, requires two picks of the weaving machine. As such, in a conventional woven product, the fill yarn is woven along the length of the warp yarns for a multiple number of machine picks, with the woven product produced defined in length by the number of filling picks of the fill yarn and defined in width by the number of warp yarns in which the fill yarn is woven therebetween.
Some damaged or diseased lumens, however, have quite complex shapes. For example, the root portion of the aorta is provided with sinuses or bulges that surround the aortic valve, which are called the sinuses of Valsalva. The diameter and orifice area of the aortic root are greater at the vicinity of the sinuses as compared to other portions of the root. With such a complex geometry, implantable grafts matching such complexity have often been made by suturing differently shaped graft components together. For example, U.S. Pat. No. 6,352,554 to DePaulis describes a method for forming a graft for the aortic root by suturing a bulbous woven section in between two straight tubular woven sections. Further, the bulbous woven section is also formed cutting or otherwise attaching woven materials. Such techniques are not only costly as numerous textile portions must be sutured to one and the other, but also serve as a potential source for leakage as it is difficult to suture fluid-tight seams among the textile components.
The present invention provides for a seamlessly woven varied diameter graft, such as but not limited to aortic root grafts, and methods for producing the same.